Latest Migration Map and DataThe migration is off to an early start this spring! Sightings have already been
reported from as far north as latitude 32 N --in Dallas and Tyler, TX and at the same latitude in Clinton, MS.
These records are at least a full week earlier than those at the same locations last year.

Here is this week's migration map, and the Spring, 1999 map for comparison:

March 15, 2000

March 16, 1999

If you live in the Gulf States, please keep your eyes on the skies--and be ready to report
migrating monarchs! Also watch your milkweed for signs of the first monarch eggs and larvae.
Field Notes from the Mexican Monarch SanctuariesDr. Bill Calvert writes from Angangueo: "After all
the reports we'd been hearing about butterflies arriving the earliest ever in the southern United States--and speculation
about the unusually warm winter driving the butterflies north prematurely--we were all little apprehensive about
what we'd find in the sanctuaries.

"Not withstanding all these negative reports and speculations, in 24 years of Mexican monarch watching, I'd
never seen the colonies break apart substantially before the 20th of March--and indeed had often seen butterflies
in substantial numbers here into early April. And when we arrived at El Rosario, our worries were totally dispelled.
We were greeted by tree, after tree, after tree, fully laden with dark, clusters of butterflies. When the sun appeared,
they filled the sky above and between the trees.

"Several of us had wandered to an area where the trees
were heavily laden with butterflies which were especially close to the ground. We were staring and photographing
when a sharp snapping sound rang out. A branch full of butterflies came down, spilling its colorful cargo all over
the ground. The butterflies immediately began to rise by opening and closing their wings. Those on the upper side
of the branch began to fly off in uniform motion and direction. Those on the bottom were trapped by the weight
of the branch. Gingerly we lifted the branch and allowed them to escape. The branch was not small--perhaps 6-7
feet in length--so many thousands had come down with it. But within one half hour only a handful were left in the
spot where the branch had fallen. So falling with a branch does not seem to harm many of them."

Math students in Florida, Maine, Wisconsin and Texas all agreed: 32,500 monarchs! Congratulations to students at:

Hillcrest Elementary of Ellsworth, Wisconsin

Lincoln School of Vinalhaven, Maine

Citrus Elementary School of Vero Beach, Florida

Vidor Middle School in Vidor, Texas

How Many Millions of Monarchs?
Discussion of Challenge Questions #7 & #8
The students in Mrs. Sollock's 5th grade class in Vidor, Texas (lsollock@esc5.net) determined that 11,375,000 monarchs
were clustered in the Sierra Chincua colony this January. If they could give 1 butterfly to each person, they could
distribute butterflies to everyone in 3 states! They used the 1990 census population totals to calculate their
answer:

"We combined 3 states' populations to total the 11,375,000. Try it! Combine the populations
of Rhode Island, New Hampshire, and Michigan. (Hint: Round all numbers to the nearest hundred thousand.)"

The Cloud Effect
Discussion of Challenge Question #10

A cloud has just blocked the sun.
Photo by Dr. L. Brower

Dr. Calvert described a behavior of the colony called the "cloud effect". When a cloud blocks the sun,
all the butterflies that were basking in the sun immediately push off into the air. He said this behavior is thought
to serve an important purpose.

Challenge Question #10 asked, "What purpose do you think is served by the behavior known as the 'cloud effect'.
That is, why do you think the butterflies suddenly fly into the air the moment the sun goes behind a cloud? What
are they trying to do?"

Fifth Grade students Kaleigh, Caitlyn & Tasha Doelman of Scott Young Public School in
Ontario, Canada replied:

"We think that the reason for the monarchs strange but incredible behavior is because
when clouds gather or hide the sun it is usually a sign of rain. Since monarchs can't fly when their wings are
wet they leave to the shelter of the trees. If they stay when it rains they would have to wait untill the water
evaporated off their wings." (KevinC.Adams@TLDSB.on.ca)

Here's Dr. Calvert's explaination: "These butterflies have no way of knowing how long
the cloud will last. If they were to remain in the exposed, basking positions without the sun, they soon may cool
down and not be able to fly. This would compel them to stay there as long as the cloud persists--which could be
overnight. By flying, they keep their body temperatures high enough to maintain mobility--either to return to basking
position when the sun returns, or to go back under the canopy if clouds remain.

"What they are undoubtedly perceiving is a sudden lack of solar radiation and rapidly falling air temperatures.
They are poikilotherms and cannot raise and maintain elevated internal temperatures without incoming radiation.
They need high internal temperatures if they are to perform daily functions such as flying, crawling, mating, etc.
At many locations and times during the winter season, nighttime radiational cooling takes surfaces exposed to the
night sky down below freezing. If trapped there, the butterflies might freeze to death. Within their clusters,
radiation and re-radiation trapped within vegetative mass of the forest and understory foliage keeps temperatures
higher - as much as 5°C higher - than the exposed surfaces. The butterflies are clearly safer within the forest.
This is where they try to go when radiation is blocked by a cloud for a long period."Life in Sanctuary Region
A Walk in the Sanctuary With Guide JavierOne of the hopes for conservation
of the monarch sanctuaries is through "ecotourism". ("Ecotourism" is a strategy for conservation
that has developed over the past decade. Ecotourism refers to tourism in a natural area, and it usually implies
that the local people can earn income from visiting tourists. This gives the people an economic incentive to protect
natural land, rather than develop it for other economic uses.)

The people who own land in the monarch sanctuaries can often earn income as tour guides. Read
today's interview with "Javier", a guide who leads tourists visiting the El Rosario sanctuary.

Challenge Question #17
"How does Javier feel about his work as a guide in the El Rosario Sanctuary? Do you think this example of
ecotourim is working well? List the problems and successes Javier mentions in his interview."

How to Respond to Today's Monarch Challenge Questions|

IMPORTANT: Please answer ONLY ONE
question in each e-mail message!

1. Address an e-mail message to: jn-challenge-monarch@learner.org
2. In the Subject Line of your message write: Challenge Question #16 (or #17).
3. In the body of the EACH message, answer ONE of the questions above.